Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

Han, Myung‐Geun; Garlow, Joseph A.; Marshall, Matthew S. J.; Tiano, Amanda L.; Wong, Stanislaus S.; Cheong, Sang‐Wook; Walker, Frederick J.; Ahn, Charles; Zhu, Yimei

doi:10.1016/j.ultramic.2017.03.028

Cited by 16 publications

(15 citation statements)

References 20 publications

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“…4) further identifies SE as the source of these signals, and also indicates that SEEBIC imaging might be used to map material work functions. Biasing the TIA's input relative to ground, we see that positive (negative) bias decreases (increases) the EBIC signal, demonstrating active SE voltage contrast without an off-sample detector [19]. Similar analysis of the conventional STEM signals shows no bias dependence.…”

Section: Resultsmentioning

confidence: 55%

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STEM Imaging with Beam-Induced Hole and Secondary Electron Currents

et al. 2018

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In standard electron beam-induced current (EBIC) imaging, the scanning electron beam creates electron-hole pairs that are separated by an in-sample electric field, producing a current in the sample. In standard scanning electron microscopy (SEM), the scanning electron beam ejects secondary electrons (SE) that are detected away from the sample. While a beam electron in a scanning transmission electron microscope (STEM) can produce many electron-hole pairs, the yield of SE is only a few percent for beam energies in the range 60-300 keV, making the latter signal much more difficult to detect on-sample as an EBIC. Here we show that the on-sample EBIC in a STEM registers both SE emission and capture as holes and electrons, respectively. Detecting both charge carriers produces differential image contrast not accessible with standard, off-sample SE imaging. In a double-EBIC imaging configuration incorporating two current amplifiers, both charge carriers can even be captured simultaneously. Compared to the currents produced in standard EBIC imaging, which only highlights the regions in a sample that contain electric fields, the EBIC produced by SE, or SEEBIC, are small (pA-scale). But SEEBIC imaging can produce contrast anywhere in a sample, exposing the texture of buried interfaces, connectivity, and other electronic properties of interest in nanoelectronic devices, even in metals and other structures without internal electric fields.

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Section: Resultsmentioning

confidence: 55%

“…Most EBIC studies have been conducted in a scanning electron microscope (SEM) [4,6]. EBIC imaging for the purpose of mapping electric fields has also been extended to scanning TEM (STEM), where TEM's better electron optics and electron-transparent samples both contribute to improved spatial resolution [11,[16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

STEM Imaging with Beam-Induced Hole and Secondary Electron Currents

et al. 2018

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“…Evaluation of the depletion region width in a NW p-n junction can be carried out through various methods, including wet chemical etching [25], secondary electron (SE) imaging [26,27], offaxis electron holography (EH) [28][29][30][31], electron beam induced current (EBIC) [32,33], Kelvin probe force microscopy [34,35], and other AFM-based techniques such as scanning capacitance microscopy (SCM) [36,37] and scattering-type scanning near-field optical microscopy [38]. Methods based on secondary ion mass spectroscopy including atom probe tomography are very powerful at mapping dopants [39], but they cannot evaluate the level of activation in the dopant impurities detected.…”

Section: Introductionmentioning

confidence: 99%

Abrupt degenerately-doped silicon nanowire tunnel junctions

Cordoba¹,

Teitsworth²,

Yang³

et al. 2020

Preprint

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We have confirmed the presence of narrow, degenerately-doped axial silicon nanowire (SiNW) p-n junctions via off-axis electron holography (EH). SiNWs were grown via the vaporsolid-liquid (VLS) mechanism using gold (Au) as the catalyst, silane (SiH 4 ), diborane (B 2 H 6 ) and phosphine (PH 3 ) as the precursors, and hydrochloric acid (HCl) to stabilize the growth. Two types of growth were carried out, and in each case we explored growth with both n/p and p/n sequences. In the first type, we abruptly switched the dopant precursors at the desired junction location, and in the second type we slowed the growth rate at the junction to allow the dopants to readily leave the Au catalyst. We demonstrate degenerately-doped p/n and n/p nanowire segments with abrupt potential profiles of 1.02 ± 0.02 and 0.86 ± 0.3 V, and depletion region widths as narrow as 10 ± 1 nm via EH. Low temperature current-voltage measurements show an asymmetric curvature in the forward direction that resemble planar gold-doped tunnel junctions, where the tunneling current is hidden by a large excess current. The results presented herein show that the direct VLS growth of degenerately-doped axial SiNW p-n junctions is feasible, an essential step in the fabrication of more complex SiNW-based devices for electronics and solar energy.

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“…For example, Krumeich et al (2011) studied catalytically active material where SEM provides topography information on the location of the metal catalyst particles on the ceramic carrier, whereas STEM gives insight into the inner structure. Pioneering work has been performed by the Zhu group (Zhu et al, 2009; Han et al, 2017) where, e.g., atomic-resolution secondary electron (SE)-SEM images and HAADF-STEM images of YBa 2 Cu 3 O 7- δ are presented. Cretu et al (2015) were able to distinguish BN and graphene based on work-function contrast SE-SEM imaging which was not possible by ADF-STEM.…”

Section: Introductionmentioning

confidence: 99%

On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope

et al. 2018

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Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.

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Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

Cited by 16 publications

References 20 publications

STEM Imaging with Beam-Induced Hole and Secondary Electron Currents

STEM Imaging with Beam-Induced Hole and Secondary Electron Currents

Abrupt degenerately-doped silicon nanowire tunnel junctions

On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope

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